H.B.Tristram (11 May 1822 - 8 March 1906) , The Natural History of the Bible: "Abraham planted a grove (eshel) in Beersheba" (Gen.XXI.33): "Saul abode in Gibeah under a tree (eshel) at Jabesh" (I Sam. XXXI.13); but, in 1 Chron. X.12, it is called 'elah,' an oak. Critics are agreed that 'eshel' signifies some particular tree, and the best authorities
identify it with the Arabic asal, the Tamarisk tree.
No less than seven species of Tamarisk are found in Palestine, and several of them in great abundance."